Masao Iwai

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This transcript is based on a video-recorded interview deposited at MarE3, JAMSTEC (Yokosuka, Japan).

The transcripts of the research project Oral Histories of Scientific Ocean Drilling are polished representations of oral conversations, and are intended solely for the purpose of preserving and documenting personal accounts and memories. They are not a literary product, and are not intended to exhibit literary qualities.

The primary goal of this transcript is to capture the spoken words and memories of the interviewee as accurately as possible. Minor editing and polishing works have been performed to enhance clarity and readability while maintaining the authenticity of spoken discourse, including non-standard grammar, inconsistencies, repetitions, and pauses.

The reader must be aware that memories of an event can vary between individuals and may evolve over time due to various factors, such as subsequent experiences, interactions with others, and personal emotions.

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Please cite the interview as:

Interview of Masao Iwai by Beatriz Martinez-Rius on 2025 April 3, Kochi Institute for Core Sample Research, Kochi (Japan). [link]

Beatriz Martinez-Rius (BMR): today is April 3rd of 2025. I am Beatriz Martinez-Rius, historian of science at JAMSTEC, and I am with Masao Iwai at the Kochi Institute for Core Sample Research. Thank you very, very much.

Masao Iwai (MI): Thank you.

BMR: Can you please say your name, your position and affiliation?

MI: My name is Masao Iwai. I’m now working as a professor and vice-director of MaCRI, the Marine Core Research Institute of Kochi University, and we are organized with the IODP Core Repository with JAMSTEC. It’s known as the KCC, the Kochi Core Center.

BMR: Do you work mostly in this building or in the university?

MI: Well, this KCC office is shared with the university and JAMSTEC, and I’ve been working in this building for the last five or seven years. Before that, I was in the main campus since I moved from JAMSTEC to university, 30 years ago.

BMR: What are your research interests?

MI: I’m originally a geologist and micropaleontologist, especially for diatom biostratigraphy. I’ve always joined the JOIDES Resolution and Chikyu expeditions as a diatom micropaleontologist. My first expedition was ODP Leg 138, in the eastern equatorial Pacific, for a palaeoceanographic expedition. After I got a job here at Kochi University, I attended the Antarctica expedition. Three of my six previous expeditions with the JOIDES Resolution were held in the Southern Ocean, so I’m now very interested in the Antarctic ice history, reconstructing by using diatom biostratigraphy.

The last expedition, IODP Exp.405 JTRACK held in 2024 fall in the Japan Trench, was my first expedition with Chikyu. It focused to drill through the plate boundary on the shallow rupture zone. Using the biostratigraphy, I reconstructed the structure of the frontal prism.

BMR: You’ve been in seven expeditions, then: six on the JR and one on Chikyu.

MI: Yes, that’s right.

BMR: How do you like Chikyu, compared to JR?

MI: Well… I’m a JR person, so I really love the ODP and the JOIDES. But… Chikyu also has gotten much better, rather than at first. I was working to establish Chikyu while I was in JAMSTEC, and I know that the first stage of the Chikyu had a plan… It was a very expensive ship, but the laboratory didn’t look so great. But after 20 years’ experience of Chikyu, I guess the Chikyu got much better organized. And in the last expedition we really succeed in drilling to the plate boundary.

BMR: We will come back later to your expeditions. Let’s start chronologically – and at some point, we will start diverging to other topics. Just to know about your background, where did you grow up?

MI: I come from Gunma prefecture. Is located 100 kilometers north from Tokyo area. No sea, no coast. My father was working as a farmer, especially focused on cows for the milk. So, I’m a cowboy (laughs), I spent the time as a cowboy when I was a kid, and I was really enjoying the country life.

BMR: That’s interesting because I feel that in Japan there are not many cows, right? It’s difficult to find cow farms compared with other countries.

MI: Well, at that time the government hoped to make this field grow in Japan. But the economic conditions for farmers were getting bad, so my father said, “you don’t mind about our field. You can do anything you want”. So, I decided to go outside of my hometown – although I’m the first boy of my family, and traditionally in Japan the first boy should take care of the family business.

BMR: To continue the family tradition. And why did you choose Earth sciences?

MI: When I was a high school student, one of my friends invited me to watch the stars with a telescope and I really enjoyed it. I tried to find such kind of department in the university, and I only found three, at that time. Tohoku University was the best place for me to have a potential to go and study astronomy. But my score was not so good (laughs), so I missed to go to the astronomical department. I had no interest in Geology, at that time, but when I started to study Geology, I really enjoyed the fieldwork in the mountain side. It was like an adventure, like I enjoyed it in my hometown when I was a kid.

BMR: There are many people that don’t think about geology until they go to the field. Was there someone to influence you or mentor you to the point that you decided to do a PhD?

At that time, the doctoral and master course students at Tohoku University were very excited about the new science, not the classical geology, but also interdisciplinary research area such as ninchikagaku (cognitive science). Fractal (and soliton) was also – now its very popular, to use a fractal picture or video, but at that time, it was a very new mathematic method, and people really enjoyed using such kind of tool to understand geology or fossils. So, everybody was excited and discussing, and I was hoping to become one of the members of such group.

BMR: And how did it happen that you learn about scientific ocean drilling?

MI: I started fieldwork as an undergraduate and I made a lot of the fieldwork on land, when I was an undergraduate and master course student. When I was a master course student, I worked on the Noto Peninsula, where the marine diatomite is. Diatom is a microfossil, and diatomite is composed of many diatoms. That was the first time that I learned about microfossils.

When I was doctoral course student, in my first year, I had no idea what I could do for the PhD, but I had a chance to join my first ODP expedition. One night, a racoon dog crossed my car. And I crashed. The day after that accident, my professor asked me, “Professor [Asahiko] Taira has made a phone call to me. He told me that he’s seeking somebody to join the expedition as a diatom biostratigrapher, and I was thinking that you could be the one”. And I decided to join that expedition. When I attended that first expedition, shipboard scientists celebrated my 25^th birthday onboard.

BMR: What do you remember in particular, about that first expedition?

MI: I was very excited because when I was in the laboratory of the university, no scientific research tools. Ony the fieldwork was the majority of the department. But, onboard, there’s many, many nice equipment, and not only the microscope but also for geochemistry, sedimentology, physical properties, p-mag…

I was very impressed. In that expedition, there were maybe more than 30 scientists from 16 countries, and that was my first time to meet such an international interdisciplinary community. I was really excited about that. But my English was very bad, at the time. Not only the speaking, but also the listening. So, I missed a lot of meetings on board. But after one month there, I succeed to discuss with the others. There was a very nice person there and I worked very hard. And people said to me, “you don’t need to work so much, go to bed!” (laughs). That time I was the first Japanese student to attend an ODP expedition by himself.

BMR: Was there any cultural shock? Something about how non-Japanese did things or behaved that surprised you?

MI: Yeah. At that first time, I couldn’t understand English. They discussed very quickly, and I felt very lonely onboard. And if the people in the corner of the laboratory laughed at me, I was like, “What? What’s happening over there?” or something like that. Sometimes we misunderstood each other, so it was a very hard time for first one month. But after, one of my co-workers in the micropaleo lab had a problem with the microscope, and they needed a technician, they couldn’t fix it by themselves. But I supported them to fix it. After that, I got much friendly. So, every – the JOIDES Resolution had a cookie time, and before that they go and I was always late to the cookie time and sometimes I missed it. But after that, always – “hi, Masao! Is cookie time!” (laughs), so I really enjoyed the discussions, even if I couldn’t speak good enough. But they understood my character – maybe I was not so bad person (laughs).

BMR: I think that in general Japanese people are very shy.

MI: Yeah.

BMR: But if you are not used to be with Japanese people, maybe you think, “what’s going on with this person? That’s alone, don’t look straight to my eyes…?”

MI: Yeah. In general, European or western people speak a lot, because they don’t care about their use of the English. But Japanese people are very shy, and have a very stressful time trying to… We learn a lot of English for more than 10 years but still, we are not good at speaking to each other because we learn a lot of grammar and not debating or discussing. Now, the education system has changed and the younger generation are getting much better.

BMR: How the first ODP expedition influence the next steps in your career?

I learned a lot during the expedition. My coworkers told me a lot, and I learned everything onboard. Maybe the basement of my PhD was established during this two-months expedition. When I moved from Sendai to Tokyo, to the ORI (Ocean Research Institute) of Tokyo University, one of the researchers who was working there moved as a research member of JAMSTEC. And he invited me to work for the new research vessel, for its establishment in Japan. The Japanese scientific drilling vessel.

I decided to work in JAMSTEC because I was very happy – I had received a lot of gifts from the ODP expedition. So, I would like to give back something to the ocean drilling community. I wanted to contribute to establish the new research vessel and the core repository, because I had experience in the JOIDES Resolution. I contributed to bring those elements in the white paper, to establish the core repository and the research vessel.

BMR: Who was part of that group, could you remember? And how was the interaction with these people? I mean, did you discuss, did you had experienced and non-experienced people… how did that work?

MI: At that time, the director of the Deep-Sea Research Department, who has physical oceanography background, was my boss, and one of the other middle career scientists, who also had experience as a petrologist, and me.  Only three people working for the OD21.

BMR: Can you remember their names?

MI: The other two have already passed away. Dr. Hiroshi Hotta, the director of the Deep-Sea Department. He was the first person who got a vice-president position of JAMSTEC from a scientist. And the other one was Dr. Jiro Naka, who graduated at Kochi University and attended ODP Leg 142 as a petrologist, after my first expedition Leg 138.

BMR: You mentioned that you contributed to put together the white paper. What kind of things did you – either as a team or you individually – envisioned or imagined about the future of a Japanese research drilling vessel?

MI: Well, the research founding at that time for the university, academic community, was very low. I thought that, for the OD21 Program, to establish the research vessel and the core repository was a very good chance to establish an international research institute, at that time. I felt a very strong emotion. Establishing the core repository was much more important. And that was very important for the Japanese scientific community to lead the science in the world. That was my impression at that time. And I wrote the strategy of the roadmap.

BMR: That’s very interesting, because normally when I talk to interviewees, we normally focus on the ship. But the ship is only a starting point to gather the data and start a collaboration. It’s not the end point. So, I’m realizing that you need somewhere where this science can develop.

MI: Yeah, yeah.

BMR: Maybe we can jump to the future for a moment. What kind of things did you imagined at that time that were part of the roadmap that have been achieved? And which ones have to yet be achieved?

MI: Unfortunately, the core repository established in Kochi – well, not unfortunately, but the building was built in Kochi, but most of the researchers were funded at JAMSTEC. So, it was separated in two parts, and Kochi University is one of the smallest national universities in Japan. So, to produce young scientists it’s hard. But the unique point of the KCC is that it completely collaborates with JAMSTEC and the Kochi University. It took us more than 20 years, but we are trying to become a more international institute. Also, after 2025 we started the IODP³ lead by Japan and ECORD. We have the flexibility to use Chikyu and other research vessels as Mission Specific Platforms, and also the legacy cores are also very important to use, like in virtual expeditions. So, hybrid expeditions are the main objective, key thing. And we have a lot of legacy data. For a human being, it will take more than half a century, and we have gotten a lot of legacy cores and data. Now, many people are interested in the big data science by using AI or some other IT technology. I guess that it’s a very nice chance for us to do those things for the next stage, IODP³. It’s a turning point.

A key point for next stage is that the stratigraphy correlation and data assimilation. Accurate correlation between site to site is very important. Which is the same time horizon, which data is compatible to each site… Such kind of accurate correlation and data assimilation is very important for better understanding of time series data from various drilled sites and to find the tipping points of Earth system. So, I think those are the key part for the next stage of earth science using deep sea cores. We had such kind of project, so called “Big data project”, last several years in Kochi. So, I hope our experienced would be passed to the younger generation during the IODP³ for the future step up of our knowledge on the Earth history.

The younger generation, in general, is starting from the study of the core without any fieldwork. It’s very hard to have a wide view. I would like to pass my experience to the younger generation.

BMR: I hope so, I hope it can pass. And now, jumping back to the OD21, when the Chikyu was being planned. What were the challenges? What were the tough parts to move the Chikyu project forward?

MI: The Japanese government wanted to install a new technology in the new research vessel. If there’s a similar equipment in every other country, they don’t want to establish a new research vessel. So, we decided to install the riser technology. But the problem was the operation cost. The tools, the riser system, the ship was getting bigger and bigger… People from the technology department said that the cost of performance was very nice – at that time. But the large ship needs more energy to operate.  A big ship will need more oil and oil cost getting high. So, the total cost was getting very high. At the biggening of we established Chikyu, the Japanese yen was still strong, however, it getting weaker comparing others, so I guess operation cost was the biggest problem, yes.

BMR: So, in the in the planning phase, it was realized that it will be a very expensive ship even to operate.

MI: Yeah.

BMR: But anyways, they put the money in.

MI: Yeah. For me, how to establish the research institute was the most important thing. Most of the people was not interested in that, but that part was very important. Our department had no good enough funds, so I always had a hard time to find budget for our research. And also, it’s a problem for good science. So, how to establish a research consortium was the key point.

Unfortunately, I didn’t have the chance to discuss that part when I was in JAMSTEC. I moved to university before we discussed about the research institute.

BMR: What kind of things did you learn during that period, on OD21, that were useful in your later career?

MI: When I was in JAMSTEC, the Deep-Sea Research Department was not only the geoscientists, but also included geochemists and biologists. We talked to each other in the same department and, although the total number was very low, it was a very compact research institute. So, we had the potential to exchange with each knowledge. The interaction with different departments was very important. That was my goodness, about spending one and a half years in JAMSTEC. It’s a very short time, but it was very a nice time.

And also, JAMSTEC is very close to the governmental offices. So, I also learned how to communicate with them. That was different from the other scientists who got a job in the university after they finished their PhD, directly.

BMR: What is particular or special, about talking to the government?

MI: Well, they are not focusing on the details. In science we are always focusing on the details. “This data is good or not?”. But they don’t care what kind of results in the future will be available, or something like that. At that time, I had some big gap between the science and the document to send to the government officer. It was just a dream (laughs), like science fiction, for me. But it was important the story (that we tell about) the science. And to achieve the story of the science is very important, for the scientists. If we didn’t make the story based on the basic data, it’s not science (laughs). But yeah, it’s very hard. If we make a big scientific story, we need to work a lot. And we need collaborators. But I guess is one of the good stresses to work in that kind of stuff.

BMR: You mean that it’s like submitting a proposal, that you need to take into account what the institution or the reviewer thinks about. You need to learn about how to write it, how to frame it for different people. You mentioned that you moved to the university just after this period in JAMSTEC.

MI: Yes, to Kochi University.

BMR: Was this related to your job at OD21?

MI: No, no. Taira-san was… When he was young, he got the first job in Kochi University. So, the Kochi University is a small university, but many good scientists grew up here. So, I tried to get the job.

Kochi is very famous for geologists, even if other people don’t know about that. Of course, when I was a high school student, I had no idea to go to Kochi (laughs), but, when I was seeking for a permanent job, Kochi was one of the best places to get a job. At that time, that’s what I believed. But when I came here, the budget size of JAMSTEC and Kochi University was completely different. I was really surprised about that. Many people said that Kochi University was a very fair place, and the building was new… But that wasn’t true, at that time. Everything was very old, so I needed to make the laboratory equipment by myself. Everything. So, I was visiting the home center…

BMR: Ah! To buy construction materials.

MI: Yes (laughs), to get materials for construction. I always visited that kind of shops.

FMR: For the laboratory. Is there any connection between bringing the core center to Kochi, and the fact that Taira-san was here, and you…?

MI: Yeah, Taira-san made the branch of Marine Geology when he was in Kochi. And their group had made a piston core in Kochi. For developing the piston corer, one of the professors visited the UC Santa Cruz or UC San Diego, Scripps. They learned the mechanisms of the core system and made one by themselves, by collaborating with a small company in Kochi. At that time, the University of Tokyo imported the corer from another country, and got only a 2-meter core by getting a 4-meter piston corer. At that time, the Kochi university had already succeeded in getting a 20-meter perfect coring system. Our colleagues working in the Kochi University were pioneers in Japan, to establish such kind of coring and research technique. (for reveal fault activity in coastal shallow water)

BMR: So, because there was this branch, there was already a group in marine geology, and it made sense to have here the core center.

MI: Yeah, and they already had a lot of cores, not only taken from the ODP leg deposit, but also from the shallow water marine deposits. They already knew how to maintain the cores and how to study by using marine cores. This is one of the reasons why the core repository was installed at Kochi University.

BMR: Also, maybe the cost. I guess that the cost, here, of having this building is cheaper than in Tokyo or Kanagawa.

MI: Yeah. To establish the building is maybe the same, but land price is totally different.

BMR: Land price, yes, exactly. How your collaboration with ODP and IODP continued after you moved to Kochi?

MI: When I got to the job here, I got a chance to attend a Southern Ocean expedition in the Antarctic Peninsula. When I was a master course student, I visited Chile – it’s a very memorial place, and I really wanted to go back there. My proposal was accepted to go onboard, and succeeded to go back to Punta Arenas.

BMR: Was it an ODP cruise?

MI: Yes, ODP Leg 178.

BMR: Your second expedition.

MI: Yes, second expedition. My first one was in the Equatorial Pacific ocean, and the second one was Antarctic Peninsula. I wanted to correlate the two areas, and there was no one working on the Equatorial Pacific or Southern hemisphere (in Japan). So, I decided to make my own field.

BMR: Did you succeed?

MI: Yeah. Leg 178 was very unique experience. The co-chief knew about the Southern Ocean coastal area and Antarctic ice history very well. That was my first experience in the Southern Ocean, so I had not so good background about that region. At the early stage at the first site, I had hard time to date the core. It was rare diatom and hard to decide which maker species was in situ and which others are reworked. But… the other data showed that it was getting older and older. When we drilled deeper and found good enough diatom, we got clear bio-stratigraphic age information, however, there was contradiction with magnetostratigraphic age interpretation. We discussed a lot, and I tried to fix it… Some people said that communication was missing…  I learned about that, and after following the advice, I had tried to communicate with the other scientists onboard. Not only focus on the microscope, but also to discuss with the other scientists.

At that time, my data was very key for the hypothesis, to try to understand this by using the cored. At that time, we found some big gap of interpretation of that age-depth model, from my side and the other (researcher’s) side. I worked based on the published age, from the prior scientists working in the Southern Ocean. But if I believed on the published age, it should be some hiatus, there. However, the magnetostratigrapher didn’t believe that. The sedimentological data also seemed to have some hiatus or erosion surface, but it was not clear. We discussed a lot, but not reached a conclusion. So, to understand what’s real, I decided to attend once again a Southern Ocean Expedition, 318, in the Eastern Antarctic ice sheet. And I found that my observation was not so bad (laughs). We found a similar problem in the other side. That means that the published age was wrong, and we needed to recalibrate the data set. That was a really exciting thing.

BMR: Did you publish all this with international scientists?

MI: Yes. One of the co-chiefs of ODP Leg 178 in the Antarctic Peninsula wanted to publish within the Scientific Report, because if we put all the post-cruise research in the Scientific Report, that people who want to know what happened after the expedition just open the scientific report and that’s enough for understand what’s going on that at cruise. But that was a turning point from other people, who pushed to publish in other international journals. Because the (ODP) Proceedings doesn’t count as impact factor. But… I published several papers in the Scientific Report. Unfortunately, not in international journal. And during the other expedition of the eastern Antarctic continent, one of my colleagues published several papers, and also one of the co-chiefs asked me to advise to one of the German-Australia PhD student to study how to run the processes, to study fossil diatoms. We collaborated with each other, and published. Finally, in the last expedition in the Southern Ocean of the western Antarctic coast we found a much, much higher resolution data. As a result, it was completely same and we got much better data. Now, I’m trying to push hard that data with my collaborators.

BMR: Why did you apply to JTRACK (IODP Expedition 405)? JTRACK is very different to the other things you’ve been doing.

MI: Yeah, the reason is that I was living in Sendai for more than ten years. And when the Tohoku earthquake occurred in 2011, I couldn’t do anything. Two months later, I visited there. Everywhere was destroyed. I was really shocked by the completely different word.

At that time, JAMSTEC had the Expedition 343 in Japan Trench. I had opportunity to work on the JFAST cores after the expedition, because there were no micropaleontologists onboard. So Nobu, Eguchi-san, requested us to dating by using some biostratigraphy and I spent a little bit of long time but we succeeded in dating by using biostratigraphy. We found a very strange structure near the decollement, plate boundary fault. So, when I heard about the JTRACK project, I shall go back onboard and show them how the biostratigraphy is working very well. And if they know about the age of the sediment onboard, they can explain much better to understand what’s happening. And discuss onboard my experience in previous ODP and IODP. I have the feeling that discussions onboard, on site, are very important. Even during on land excursions – when we discuss in front of the outcrop, that’s very important.

So, I decided to attend JTRACK, and I really succeeded to date the cores. I believe that it gave a big impact for the other onboard scientists, and they also kindly told me the structure change or sedimentary change. We had the opportunity to take a sample from such kind of strange structure onboard. That is the key point, and we really succeeded in getting the collaboration onboard. That was based on my experiences onboard of the JOIDES Resolution.

BMR: You mean that after your first expedition, you kind of learn a new way of doing science.

MI: Yeah, yeah.

BMR: In the sense that you need to talk with people from other disciplines and specialties, as the only way to do better research.

MI: When I attended the first or second expedition, I was young, and I really wanted to publish papers as first author. So, I tried to close key information. But that’s not so good idea. To open all of the data, discuss it with each other… That is a step to go to a higher level. That’s what I learned form lots of expeditions.

BMR: That’s great. Maybe we can start to wrap up the interview. Let me ask you first if there’s something that I haven’t asked you, that you’d like to explain or talk about?

MI: Do you have any other question?

BMR: sure, I have more questions! (laughs) What has been the most valuable or rewarding part of being involved in scientific ocean drilling throughout your career?

MI: Well, my science is mainly composed with the ocean drilling program. Before my retirement, I would like to pass my experience the younger generation. That is the key point. Yeah. I really enjoyed my research based mainly on ODP and IODP expeditions. And it was really nice, because I could travel worldwide, to many countries, and make many friends from different countries. It’s my takaramono [treasure, precious thing].

So… It’s the most important thing for my life. And I’d like to pass how exciting it is – of course we have hard times, sometimes very hard times onboard, and sometimes I cannot publish the data good enough or have troubles; but still all this, it’s a very nice memory for me. And I’d like to pass my experience to the younger generation.

I hope this great scientific program continues. I believe that the US will come back to the international community once again. That is my dream. And of course, before such kind of long roadmap after my retirement, before that, I need to make some… climate project in the Pliocene or Miocene age. My supervisor, who attended DSDP Leg 3, also attended the CLIMAP project, which was trying to reconstruct the sea surface temperature and salinity in the glacial age. I’m trying to understand the future climate by using the legacy cores, to establish the warm Pliocene climate map, to understand what is the key role that changed the climate system. And how that will be recovered, and what will be difficult from the modern and the past.

It’s very important to understand such kind of information from ocean drilling or the sedimentary record. We cannot simulate it without any constrain. As a geological record, it should have some information about that, and constrain much better the simulations to understand the future. Otherwise, we always will have a very sad story. For the risk management, to understand the past episodic climatic change is important. And how the biota survived such kind of natural hazard is very important to understand what will be happening in our future as human beings.

BMR: That’s great. Well, with this we can close the interview. Thank you very much. It was a very great pleasure.

MI: Thank you very much.